|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
In the retina, amacrine cells modulate the transfer of information from bipolar to ganglion cells. The nature of the modulation depends on the synaptic input and the membrane properties of the cells. In the retina of white bass, we identified a class of bistratified, wide-field amacrine cell characterized by immunopositive labelling for GABA and calmodulin. In isolation, the cells presented resting membrane potentials averaging -69 mV although some cells settled at more depolarized values (-30 mV). Injection of depolarizing current pulses induced oscillatory membrane responses. When elicited from depolarized cells, the oscillations were short-lived (< 40 ms). For the most part, the oscillatory potentials of hyperpolarized cells remained unattenuated throughout the depolarizing pulse. The frequency of the oscillations increased logarithmically with mean membrane potential, ranging from 74 to 140 Hz. Cells exhibiting depolarized membrane potentials oscillated at twice that rate. When the membrane potential of these cells was hyperpolarized to -70 mV, the oscillations became unattenuated and slowed. We found the cells expressed voltage-gated sodium, potassium and calcium currents and calcium-dependent potassium currents. We demonstrate that the oscillatory potentials arose as a result of the interplay between calcium and potassium currents. The cells responded to local application of GABA and glycine, both of which modulate the oscillatory potentials. Glutamate and its analogues depolarized the cell and induced oscillatory potentials. Our results indicate that oscillatory responses of a type of wide-field amacrine cell are an intrinsic feature of the cell and not due to circuit properties.
This article has been cited by other articles:
![]() |
J. Petit-Jacques and S. A. Bloomfield Synaptic Regulation of the Light-Dependent Oscillatory Currents in Starburst Amacrine Cells of the Mouse Retina J Neurophysiol, August 1, 2008; 100(2): 993 - 1006. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. M. Ackert, S. H. Wu, J. C. Lee, J. Abrams, E. H. Hu, I. Perlman, and S. A. Bloomfield Light-induced changes in spike synchronization between coupled ON direction selective ganglion cells in the mammalian retina. J. Neurosci., April 19, 2006; 26(16): 4206 - 4215. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Petit-Jacques, B. Volgyi, B. Rudy, and S. Bloomfield Spontaneous Oscillatory Activity of Starburst Amacrine Cells in the Mouse Retina J Neurophysiol, September 1, 2005; 94(3): 1770 - 1780. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. Arai, Y. Yamada, T. Asaka, and M. Tachibana Light-Evoked Oscillatory Discharges in Retinal Ganglion Cells Are Generated by Rhythmic Synaptic Inputs J Neurophysiol, August 1, 2004; 92(2): 715 - 725. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Nakajo and Y. Okamura Development of Transient Outward Currents Coupled With Ca2+-Induced Ca2+ Release Mediates Oscillatory Membrane Potential in Ascidian Muscle Cells J Neurophysiol, August 1, 2004; 92(2): 1056 - 1066. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. A. Steffen, C. A. Seay, B. Amini, Y. Cai, A. Feigenspan, D. A. Baxter, and D. W. Marshak Spontaneous Activity of Dopaminergic Retinal Neurons Biophys. J., October 1, 2003; 85(4): 2158 - 2169. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Vigh, E. Solessio, C. W. Morgans, and E. M. Lasater Ionic Mechanisms Mediating Oscillatory Membrane Potentials in Wide-Field Retinal Amacrine Cells J Neurophysiol, July 1, 2003; 90(1): 431 - 443. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |